The study is designed as a randomized, controlled trial with specific observational objectives. All HIV-seropositive pregnant subjects electing to breastfeed their child will be counselled to exclusively breastfeed through 4 months of age. All live-born children will be randomized (1:1) at birth to one of two counseling programs: A) to encourage abrupt weaning at 4 months of age, or B) to encourage exclusive breastfeeding through 6 months of age with the introduction of typical weaning foods ad lib.